GB619758A - Stabilisation of halogenated ethylenes containing fluorine - Google Patents

Abstract

Halogenated ethylenes containing at least one fluorine atom are stabilized by incorporating therewith from 0.001 per cent and 5 per cent by weight of a compound containing an amino-nitrogen group. In the examples, tetrafluorothylene is stablized in the liquid phase by the addition of ammonia, p-phenetidine, di-n-butylanime and tri-n-butylamine respectively and in the vapour phase by tributylamine. Other examples of halogenated ethylenes which may be stabilized are vinyl fluoride, 1 : 1-difluoroethylene, 1-fluoro-1-bromoethylene, 1-fluoro-2-chloroethylene, 1 : 2-difluoro-1 : 2-di-chloroethylene, 1 : 1 - difluoro - 2 : 2 - dichloroethylene and 1 : 1 : 21 - trifluoro - 2 - chloro ethylene. Other stabilizing agents specified are primary aliphatic amines, such as ethylamine; secondary aliphatic amines such as dihexylamine and methylbutylamine; primary aromatic amines such as beta-naphthylamine and aniline; secondary aromatic amines, such as diphenylamine and phenyl alpha-naphthylamine; tertiary aromatic amines, such as triphenylamine; mixed secondary amines, such as N-monomethylaniline and N-propyl aniline; and mixed tertiary amines such as N-dimethyl aniline and N-butyldiphenylamine. Amines containing alkaryl or aralkyl groups may also be used. The stabilizer may be removed from the fluoroethylene prior to polymerization by fractional distillation, scrubbing with an acid solution or passing the gas over an absorbent for the stabilizer.